During the late Middle Ages this name was typically among the five most common for English males (with John, William, Robert and Thomas). It remained fairly popular through to the modern era, peaking in the United States in the 1940s and in the United Kingom a bit later, and steadily declining since that time.
Famous bearers include two German opera composers, Richard Wagner (1813-1883) and Richard Strauss (1864-1949), as well as British explorer Richard Burton (1821-1890), American president Richard Nixon (1913-1994), American physicist Richard Feynman (1918-1988), British actor Richard Burton (1925-1984) and American musician Little Richard (1932-2020).
In the United States this name steadily grew in popularity through the 1950s and 60s. It shot up the charts after the release of the 1970 movie Ryan's Daughter. Within a few years it was in the top 20 names, where it would stay for over three decades. Famous bearers include the Canadian actors Ryan Reynolds (1976-) and Ryan Gosling (1980-).